Rashi: It is the noise (thunder) when He gives an abundance of water.

Radak: This is a noise when it begins to rain. We serve Him also because He gives rain - "ha'Nosen Matar Al Pnei Aretz" (Iyov 5:10). The idols do not give rain - "ha'Yesh b'Havlei ha'Goyim Magshimim v'Im ha'Shamayim Yitnu Revivim" (14:22). We are Hashem's portion, and thank Him, for He has the ability to do everything mentioned. The Shamayim does not give rain - it does not have water. He gives it, after He raises clouds from the end of the land, like it says "v'Ed Ya'aleh Min ha'Aretz v'Hishkah Es Kol Pnei ha'Adamah" (Bereishis 2:6). Water does not rise from the ground, only Ed (a cloud). Hashem lifts it via the nature that He put in it. He puts water in the air via the power He put in it.

Malbim: The sound calls and publicizes His Hashgachah.

Malbim: This is where the clouds ascend to; it is called Raki'a and Shamayim in Ma'ase Bereishis.

Radak: This is like the prefix Vov in "va'Yered me'Asos ha'Chatas veha'Olah" (Vayikra 9:22) - after he descended from doing the Olah, "he lifted his hands to the Am and blessed them." (It is written earlier in the verse; the Vov teaches that it was after.) The same applies to "Atah Katzafta v'Necheta" (Yeshayah 64:4)- after we sinned, You became angry. Also here, He gives water after raising clouds. There is a special place in the air where the cloud returns to be water.

Rashi: They are clouds. Malbim - they rise from the ground and gather in a place of heavy rain clouds.

Radak: Philosophers say that they come from the north and south corners of the world - the corners far from civilization.

Radak: This is a great wonder, that lightning comes with rain. Lightning is fire, and the water does not extinguish it!

Malbim: When Hashem wants to send rain, he separates the element of fire and electricity, and there is lightning, and via this the Ru'ach leaves the clouds, and rain falls, like is known via science.

Radak: Raising clouds from the ground causes rain, and there is wind. Two Edim rise from the ground. He calls them Nesi'im, for they rise from the ground. One is moist - it is called Ed, and rain comes from it. One is dry; it is called Kitor ¹ .